Photon Raises $4.5M to Bring AI Agents Into Messaging Apps

AI infrastructure startup Photon has raised $4.5 million in seed funding to build tools that let developers deploy AI agents through messaging services rather than standalone mobile apps.

Photon says more than 40,000 developers have signed up for its platform, while revenue has grown tenfold in four months. The company supports agents that can operate through iMessage, WhatsApp, Telegram, SMS, RCS, email, voice and other communication channels.

Photon is betting on agents over apps

The startup’s thesis is that users increasingly prefer interacting with services inside messaging platforms they already use, rather than installing new apps. Photon provides developers with a unified API, an extensible channel framework, a command-line interface and observability tools to build and operate those experiences.

Photon made that message explicit at an event in San Francisco on September 17, where it held a tongue-in-cheek “funeral” for mobile apps alongside a developer gathering featuring speakers from companies including Vercel, Stripe and OpenAI.

Co-founder and CEO Daniel Tian said the transition from apps to agents will take time but believes the direction is clear. The company sees messaging as a distribution advantage because users can interact with an agent without first discovering and installing a separate application.

From open source project to managed platform

The idea grew out of work by Tian and co-founder Ryan Zhu, who had built consumer apps and repeatedly faced the same challenge: getting users to discover them. An iMessage bot they later open-sourced gained traction with thousands of developers, encouraging the founders to focus on the technology full time.

Photon says the open-source version still accounts for about 98% of usage. In April, the company introduced a hosted subscription platform offering 99.95% uptime along with SOC 2 Type II and HIPAA compliance.

The startup says its platform now has paying customers across fintech, consumer AI and other categories. It reports messaging volume increased fivefold in the past month and churn remains below 3%, although the company has not disclosed revenue figures.

$4.5 million seed round backs further expansion

Photon’s seed round was co-led by Gradient and A*, with participation from Vercel, HongShan, Z Fellows, Llama Ventures, Karman and angel investors.

The company also works with infrastructure and framework partners including Vercel, Nous Research, LangChain, Mastra, Convex, Render, Railway and Telnyx. Photon says its technology reaches millions of end users through its hosted and open-source products.

Longer term, Tian sees Photon expanding beyond communication between people and AI agents toward communication between agents themselves. In that model, one assistant could call specialised agents for tasks such as booking flights or hotels, creating an agent-to-agent layer behind a user’s conversation.